Grateless furnace and force draft for the same



A. I. THOMAS. GRA TELESS FURNACE AND FORCE DRAFT FOR THE SAME. v

APPLICATlQN FlLED AUGJQ, I920- 1,41 0, 14 1. Patented Mar. 21, 1922.

2 SHEETS-SHEET 1- 7 --7 0' D0 //a 7 o o o 0 16, 0 W? o o 0 o INVENTOR. ri a u AZ AZ 'l Y ATTORNEY;

AJI THOMAS. GRATELESS FURNACE AND FORCE DRAFT FOR THE SAME.

APPLICATION FILED AUG.I9, 1920. 1,410, 141. Patented Mar. 21, 1922; 2 $HEETS'SHEET 2.

INVENTOR. @JM

U. 1 ...i/ 5 m :12 Ha w l 1 t y w I E M Q7, w u

Ar rawEa s UNITED STATES PATENT, oFFlcE.

ALONZQ I. THOMAS, OF DALLAS, OREGON.

GRATELESS FURNACE AND FORCE DRAFT FOR THE SAME.

Specification of Letters Patent. Patented R131, 21, 1922,

Application filed August 19, 1920. ser al Ito/404,708.

tion for a furnace adapted to burn saw dust or other fine, or wet or partly wet fuel.

It isa primary object of the invention to provide a furnace in which grate bars may I be entirely eliminated. The upkeep of the grate bars constitutes the greatest item of expense in connection with the maintenance of furnaces. In the Dutch oven furnace, which is used in a great number and indeed in the majority of mills and wood working factories, the furnace is built in front of the boiler and the fuel is fed into the furnace and the heat is carried back over the bridge wall and into the boiler. This fuel, usually consisting of saw dust, piles up in a large mound directly under the stoke hole, sometimes to a depth of four feet. Thus the greater part of the draft is around the edges of the fuel and all the pile of hot fuel is supported by the grate bars. These grate bars become so hot that the weight of the fuel bends them down or expands them out of shape, so that frequent replacement of the grate bars becomes necessary. Furthermore, very little air can get through the grate bars in the center of the fire, with natural draft, because of the extreme depth of the fuel.

According to the present invention the grate bars are taken out entirely and the bottom of the combustion chamber consists of a solid floor of brick, preferably fire brick. Perforated air pipes are disposed to extend around three sides of the fire box and in addition perforated headers extend through the floor of the combustion chamber and thus dispose in the mass of fuel, at a large number of points, means for introducing a blast of air directly to the heart of the mass of fuel. This not only results in eliminating grate bars but it renders it possible to control the draft in such a way as to get the most effective results. In furnaces of ordinary construction, where wet or green fuel is used, or the atmosphere is improper for good combustion, proper results cannot be secured.

\Vith the forced draft mechanism herein shown and described the draft may be reg.- ulated to anicety and just the amount of air may be supplied to secure the best results.

Further objects and advantages of the invention will be set forth in the detailed description which now follows.

' In the accompanying drawings:

Figure 1 is a longitudinal sectional view of a furnace constructed in accordance with Y the invention; 7

Fig. 2 is a transverse, vertical S6Ct1011- therethrough. p 1

Fig. 3jisa horizontal section; and Fig. 1 is a plan view of the combustion chamber illustrating a slightly modified form of the device. 7 I

Like numerals designate" corresponding parts throughout the several figuresof'the drawing.

In the drawing the numerals 5 and 6 designate the side walls of the fire box or combustion chamber of my improved furnace and6 designates the top thereof. The

floor or bottom of the combustion chamber is solid and imperforate except where headers 7 project therethrough. This floor, 8, takes the place of the usual grate bars and supports the fuel introduced through a stoke hole 9. The products of combustion pass rearwardly over a bridge wall 10 in the manner common in furnaces of this type.

other, if the condition of the fire demands it.

Perforated air supply pipes 16, 17 and 18 are disposed along the sides of the combustion chamber and the pipe 18 is divided by a blind flange 19, the space upon each side of which is separately supplied with air through supply pipes 20 and 21, having individual controlling valves 22 and 23 therein, so that more air may be supplied to the pipe 16 than to the pipe 17 and vice versa if the condition of the fire demands it. The several pipes are united by fittinhgs 24 with which the pipes have a driving t. In other Words the pipes are not threaded but are tapered to engage 'in the fittings 24:. In like manner the headers are engaged with pipes 12. Thus it is only necessary to strike these pipes a few blows with a hammer in order to loosenand remove them, if they are burned out and it becomes necessary to replace them. a

In the modified form of the invention illustrated in Fig. 4, I have shown a plurality of stoke holes 9 in the top of the furnace, oneabove each of the headers. This renders it possible to'deposit the fuel in such manner that each header will be the center of amass of the fuel. Furthermore, this aids in eliminating the necessity for some stoking, or manipulation of-the fire through the doors in the front of the furnace. e a

It is to be understood thatthe invention 20 is not limited to the precise construction set forth. -It maybe used in furnaces of other types than those herein shown and described and it; includes within its purview whatever changes fairly come within either 2 the terms or the spirit: of the appended claims. h a

Having,described;my invention what I claim is: a

1. A device of the character described liaimwtail to on; margin t; I? am H comprising a combustion chamber having a solid bottom, a perforated pipe extending across the front of the furnace, perforated pipes extending along each side of the furnace, the 'perforatedpipe extending across the front oftlie furnace being divided into two parts, connections between the ends of said two parts and the perforated pipes which extend along the sides of the furnace, individual air supply pipes for the two parts of said divided pipe, individual con trolling valves for each of said supply pipes, a pair of lead pipes extending longitudinally beneath the bottom of the furnace andupon opposite sides of the center thereof, individual air supply pipe for said lead pipe, individual controlling valves in the ,last named supply pipe and a plurality of'headcrs upstanding from each of the leadipipes and projecting through the bottomof the furnace and perforated abovethe bottom of the furnace for the passage of.- air. 2. A structure as recited in claiin 1 Wherein the said pipes are united to each other by drive joints. y 4

In testimony whereof I hereunto aflix my signature.

Y ALoNjz oi; THOMASQY 

